Download FLI Offset Guider Manual

David Barnaby
Page 1
6/28/2017
FLI Offset Guider Manual
Bell Observatory
Purpose
This document instructs observers how to effectively operate the FLI Maxcam (CM9) camera as an offset
guider on the Bell 0.6m telescope. This assumes use of ACEOPS Oct 2002 (or later) and MaximDL 3.
Description
The CM9 is a fast, barely-cooled CCD made by Finger Lakes Instruments (FLI). The format is 512x512
pixels, and the pixel area covers 21x21 microns. Mounted at the guider port, the FOV is EW=335 arcsec
and NS=335 arcsec. The CM9 is connected directly to the ICC, and we use MaximDL to control it. The
CM9 obtains power from the UPS through outlets on the telescopes pier just as the AP2P does. Thus,
there is no need to power up outlets separately.
Procedure
STARTUP
1) CONNECT the CCDs in MaximDL as normal. You should see “Finger Lakes” (meaning the CM9)
listed as the Autoguider.
2) Enable COOLER ON. The CM9 does cool slightly, but will never reach the setpoint of –10C.
SETUP the CM9 as the OFFSET AUTOGUIDER
1) Set up the guider. The guider camera is operated using the GUIDE tab in the MaximDL GUI. Set the
GUI to Expose and enable Watch Star. To take an exposure with the guider, dial in an exposure time
and hit START. NB: we can detect a 10th mag star in the guider in 4 seconds. 4 seconds is as long as
you will probably want to integrate, and 0.2 seconds is about as fast as the CM9 can go with any
quality.
2) A separate window will pop up with the image. Currently, North is up, but West is to the left! This
matches the X-Y stage cartoon in ACEOPS. You can reverse the E-W axis with the EDIT/MIRROR
function, but succeeding images may disable the MIRROR, which can make finding a star confusing.
3) If you wish to check the settings, click Settings and you will go to settings dialog. NOTE! This is
dangerous territory, so set only the parameters you need to set and leave the rest alone! Currently, we
prefer to enable Auto Dark, X-axis, and Y-axis. We are setting the Aggressiveness at 10 (the highest
value) and there should be no reason to change it. We also recommend leaving the maximum move at
its largest allowed value of 3.0. If you dial in a new values, hit OK and you are back on the Guide tab.
USING the CM9 as a GUIDER
Before ACEOPS will respond to autoguider commands, its autoguider port must be enabled. By default,
ACEOPS launches with the autoguider disabled.
1. In ACEOPS Setup/User Corrections, disable PEC.
2. Open the Instruments menu at the top of the ACEOPS desktop, and select Auto Guider display. This
opens the autoguider control panel.
2.1. At the top of control panel, toggle the Control Status to ON (you DO NOT have to select N or S).
2.2. Now, the box labeled Auto Guider at the lower left of ACEOPS desktop should indicate ON.
2.3. It is wise to keep the autoguider control panel on the ACE desktop, since many ACEOPS
functions appear to turn the autoguider off. [NB- any slew command will automatically turn off
the autoguider port. This is a GOOD feature, but it means that YOU have to remember to turn on
the guider port in the control panel.]
2.4. Set the gain at the bottom of the control panel by sliding the bar. Different guide stars require
different gains. Here is a rule of thumb:
If guide star exposure time is
0.2 – 1.0 sec
1.0 – 3.0 sec
> 3.0 sec
Then set gain to
25  5
20  5
15  5
David Barnaby
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Once you have acquired your science object in the AP2, you can find a guide star by nudging the X-Y
stage using ACEOPS. The hole in the offset mirror is about 1400 arcsec in diameter and maybe 1200
arcsec in height. Thus, you will have to move the stage on the order 700 arcsec radially to be looking
at the offset-guider mirror. X-Y stage limits (approximately): EW= –1320 to +2300, NS=-1630 to
+1330. [NB – positive values are East and North, negative values are West and South.]
On the Guide tab, set the Declination to the declination of your science object.
When the X-Y stage is positioned, take a guide exposure of appropriate length, and locate the guide
star in the image. Select the Track function, and click in the guider image on the center of the guide
star. Now, on the Guide tab click Start.
You should see a small 8 arcsec by 8 arcsec image appear containing your guide star. MaximDL and
ACEOPS will now attempt to keep the guide star in the box for as long as you like.
Continue with science imaging or focusing as normal.
When finished guiding, turn the autoguider off in the ACEOPS control panel. We recommend that you
also turn off the guider in MaximDL. Before you SLEW or OFFSET in ACEOPS, disable the guider!
SHUTDOWN
1) Shutdown the CM9 in MaximDL using the DISCONNECT button on the Setup tab. Note: this will
disconnect the AP2 also, so do this only after you are COMPLETELY done with the AP2.
Trouble Shooting
1) The AP2 display is all white and the range is 0-255. Solution: close the AP2 image windows … all of
them! Next, using the GUI take a 1-second normal image. The AP2 should appear normal now.
2) Upon CONNECT in MaximDL, an error pops up announcing non-availability of a CCD. MaximDL
treats its suite of cameras as a single unit, and thus if one camera in the suite is not accessible, all
cameras may be affected. Solution: one of the CCDs in not powered up, probably because it is not
plugged into the pier or the back of the ICC. If the CM9 is not needed, you can indicate “No Camera”
in the GUIDER box of the Setup tab prior to hitting CONNECT. Otherwise, plug the power cord for
the camera into the mount.
3) Telescope makes an effort to slew or offset, but halts. Solution: did you Stop the guider? If not,
Cancel Move in ACEOPS, then disable the guider. The telescope will slew and offset now, but do not
be surprised if you have to reacquire a star and reset the encoder.
4) The ACEOPS autoguider port appears to turn itself off at odd times. Solution: it is designed to do so,
and various ACEOPS tasks do this automatically, including Slews. Did you slew just before guiding?
5) I cannot see the guide star, or it keeps fading in and out of view. Solution: if it’s cloudy or hazy, your
guide star may be too faint to acquire regularly. Sorry! Disable the guider, and find a brighter guide
star or wait for clearer skies.
6) I can see my guide star, but it wanders out of the FOV. Solution: is the autoguider port in ACEOPS
enabled? If so, try decreasing the gain in increments of 5.
7) The X-Y stage claims it won’t move any farther. Solution: on the X-Y stage tab, hit initialize. The X-Y
stage will move to the lower left until it reaches about –1320, -1630. Now ACEOPS knows where it is
and all should be well.
8) After using the guider, the ACEOPS offset tab fails to work reliably, especially in the NS direction.
Solution: notify the astronomer on call and note this in the log. A work around is to use the ACE soft
paddle for offsets.
Sources
1) MaximDL/CCD User Manual.